When manufacturing mineral wool fibrous insulation material, the mineral fibres are produced in a continuous web which is then cut into slabs in a predetermined size by using a transverse cutting arrangement of the above-mentioned kind on the manufacturing line. An example of such transverse cutting arrangement with two circular pendulum saw blades is known from WO 2008/154902. Often the mineral fibre web moves at a constant velocity along the web path, and the cutting arrangement follows this movement during the cutting operation to ensure a orthogonal transverse cut.
In relation to the cutting of the web of mineral fibrous material into slabs, pendulum saws are advantageous since the transverse cut can be done in a single swing action across the web for a fast and reliable cut while the web is being advanced with a continuous velocity. However, a pendulum saw with a circular saw blade mounted on a swivel arm are generally limited to a certain web thickness. If the thickness of the web is increased above a certain value relative to the radius of the circular saw blade and the length of the swivel arm, the saw cannot cut the entire web. If a single pendulum saw is used there is also a limitation with regard to the width of the web. These limits may be widened by the provision of two pendulum saws such as described in WO 2008/154902.
The demand for mineral wool insulation products is calling for increasingly thicker insulation products in order to meet the insulation requirements in modern buildings. This causes a need to adapt the production equipment accordingly. Irrespective of whether the pendulum saw arrangement has one or two pendulum saw blades, if the web thickness is increased an increase of the diameter of the circular saw blade would extend the capacity of the transverse cutting arrangement and thereby solve a potential problem if the production line is to be adapted for the manufacture of a mineral wool fibrous product with an increased thickness.
The drawback, however, with this solution is that the weight and the moment of inertia of the saw blades are considerably increased. This requires larger equipment and thereby induces a substantial increase in the costs, in particular if the dimensions of a certain transverse cutting apparatus are reached and a new and bigger apparatus is required.